Conveyor rollers are generally manufactured by forming or machining a drum (often hollow) from tubing, pipe, or other similar solid material. Typical designs for conveyor rollers include a metal shaft with a roller body made of metal tubing or pipe, with end disks added to “plug” the ends of the roller body. Plastic conveyor rollers are also known, wherein dense/solid plastic is cast or otherwise formed about a shaft to define the roller body. Such plastic rollers may include “torque coupling” structure protruding from the shaft into the plastic roller body to promote adhesion between the shaft and the roller body. As an example, the Ralphs-Pugh Co. (Benicia, Calif.) produces tapered conveyor rollers having urethane roller bodies, with the roller bodies somewhat resembling hard rubber. Ralphs-Pugh also makes tapered rollers of compressible foam, wherein the foam roller bodies are preformed and fit over a shaft (or a smaller-diameter roller). Such compressible rollers are often used on roller conveyors wherein products ride directly on the rollers (with the “soft” rollers avoiding damage to the products), and are also often used as “pinch rollers” wherein opposing rollers sandwich and compress matter (e.g., a paper web).
Conventional rollers tend to be costly, in part due to the material and manufacturing costs of the roller components (drum, end disks, etc.) and the need to assemble these with some degree of precision (to avoid eccentricity/rotational imbalance, surface defects which may damage belts or other matter carried on drum surfaces, etc.). Further, typical rollers have high mass and inertia, and less than ideal dynamic properties.
Thus, a long-felt need exists for conveyor rollers which are more quickly, easily, and economically manufactured, and which have lower weight and better dynamic properties.